OCILB – Refrigeration Contractor
Examination Questions and Correct
Answers (Verified Answers) Plus Rationale
2027 Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration system?
A. To create cold directly inside the evaporator
B. To convert electricity into cold air
C. To remove heat from a space or product and reject that heat
elsewhere
D. To increase the pressure of the conditioned space
Rationale: Refrigeration is fundamentally a heat-transfer process. The
system absorbs heat from the refrigerated space or product at the
evaporator and rejects that heat to another location, normally through
the condenser.
2. Which component is responsible for rejecting heat from the
refrigerant to the surrounding environment?
,A. Evaporator
B. Expansion device
C. Compressor
D. Condenser
Rationale: The condenser receives high-pressure, high-temperature
refrigerant vapor from the compressor and transfers heat from the
refrigerant to the surrounding air or water. As heat is removed, the
refrigerant condenses into a liquid.
3. What is the primary function of the compressor in a vapor-
compression refrigeration system?
A. Remove moisture from the refrigerant
B. Raise the pressure and temperature of the refrigerant vapor
C. Convert liquid refrigerant into low-pressure liquid
D. Reduce condenser pressure
Rationale: The compressor draws low-pressure vapor from the
evaporator and compresses it into a high-pressure, high-temperature
vapor. This pressure increase allows the refrigerant to reject heat
effectively in the condenser.
4. Which component meters refrigerant entering the evaporator?
,A. Receiver
B. Accumulator
C. Expansion device
D. Condenser fan
Rationale: The expansion device controls refrigerant flow into the
evaporator and creates the pressure drop necessary for evaporation.
Common devices include thermostatic expansion valves, electronic
expansion valves, and fixed metering devices.
5. What happens to the pressure of a refrigerant as it passes through
a properly operating expansion device?
A. It increases sharply
B. It remains constant
C. It decreases
D. It becomes atmospheric
Rationale: The expansion device separates the high-pressure side from
the low-pressure side. The resulting pressure reduction causes part of
the liquid refrigerant to flash into vapor and lowers its saturation
temperature.
6. In a typical refrigeration cycle, where does the refrigerant absorb
heat from the refrigerated space?
, A. Compressor
B. Condenser
C. Receiver
D. Evaporator
Rationale: The evaporator is the heat-absorbing component. Low-
pressure refrigerant enters the evaporator and absorbs heat from the
surrounding air, product, or secondary fluid as it changes toward vapor.
7. What condition is normally desired at the compressor inlet?
A. High-pressure liquid
B. Saturated liquid
C. Superheated vapor
D. Subcooled liquid
Rationale: Compressors designed for vapor-compression refrigeration
should receive vapor rather than liquid. A controlled amount of
superheat helps prevent liquid refrigerant from entering the compressor
and causing damage.
8. What is superheat?
A. The temperature below the saturation temperature
B. The pressure difference between suction and discharge
C. The temperature of a vapor above its saturation temperature at a
Examination Questions and Correct
Answers (Verified Answers) Plus Rationale
2027 Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration system?
A. To create cold directly inside the evaporator
B. To convert electricity into cold air
C. To remove heat from a space or product and reject that heat
elsewhere
D. To increase the pressure of the conditioned space
Rationale: Refrigeration is fundamentally a heat-transfer process. The
system absorbs heat from the refrigerated space or product at the
evaporator and rejects that heat to another location, normally through
the condenser.
2. Which component is responsible for rejecting heat from the
refrigerant to the surrounding environment?
,A. Evaporator
B. Expansion device
C. Compressor
D. Condenser
Rationale: The condenser receives high-pressure, high-temperature
refrigerant vapor from the compressor and transfers heat from the
refrigerant to the surrounding air or water. As heat is removed, the
refrigerant condenses into a liquid.
3. What is the primary function of the compressor in a vapor-
compression refrigeration system?
A. Remove moisture from the refrigerant
B. Raise the pressure and temperature of the refrigerant vapor
C. Convert liquid refrigerant into low-pressure liquid
D. Reduce condenser pressure
Rationale: The compressor draws low-pressure vapor from the
evaporator and compresses it into a high-pressure, high-temperature
vapor. This pressure increase allows the refrigerant to reject heat
effectively in the condenser.
4. Which component meters refrigerant entering the evaporator?
,A. Receiver
B. Accumulator
C. Expansion device
D. Condenser fan
Rationale: The expansion device controls refrigerant flow into the
evaporator and creates the pressure drop necessary for evaporation.
Common devices include thermostatic expansion valves, electronic
expansion valves, and fixed metering devices.
5. What happens to the pressure of a refrigerant as it passes through
a properly operating expansion device?
A. It increases sharply
B. It remains constant
C. It decreases
D. It becomes atmospheric
Rationale: The expansion device separates the high-pressure side from
the low-pressure side. The resulting pressure reduction causes part of
the liquid refrigerant to flash into vapor and lowers its saturation
temperature.
6. In a typical refrigeration cycle, where does the refrigerant absorb
heat from the refrigerated space?
, A. Compressor
B. Condenser
C. Receiver
D. Evaporator
Rationale: The evaporator is the heat-absorbing component. Low-
pressure refrigerant enters the evaporator and absorbs heat from the
surrounding air, product, or secondary fluid as it changes toward vapor.
7. What condition is normally desired at the compressor inlet?
A. High-pressure liquid
B. Saturated liquid
C. Superheated vapor
D. Subcooled liquid
Rationale: Compressors designed for vapor-compression refrigeration
should receive vapor rather than liquid. A controlled amount of
superheat helps prevent liquid refrigerant from entering the compressor
and causing damage.
8. What is superheat?
A. The temperature below the saturation temperature
B. The pressure difference between suction and discharge
C. The temperature of a vapor above its saturation temperature at a
